楔形光纤与半导体多量子阱平面光波光路芯片的耦合分析

采用楔形光纤(WSF)实现了与半导体多量子阱(MQW)平面光波光路(PLC)芯片的高效耦合。在多量子阱-平面光波光路前置模斑转换器(SSC)和不加模斑转换器的情况下,用阶梯串联法(SCM)数值模拟并优化设计了楔形光纤-平面光波光路间最佳耦合参量:楔形光纤楔角45°、端面圆柱透镜曲率半径2.5μm、模斑转换器-多量子阱-平面光波光路出射椭圆光斑长半轴3.5μm、纵横比5、楔形光纤-平面光波光路间垂直方向和水平方向无偏移、纵向间距5.5μm。用反向推演法(IDM)实验分析了楔形光纤样品的出射光场,与阶梯串联法(SCM)计算结果相比长轴误差为3.125%,短轴误差为0.8%。建立楔形光纤-平面光波光路-单模光纤(SMF)的耦合实验系统,在1.55μm波长处以单模光纤作为出纤的相同条件下,发现楔形光纤激励入射平面光波光路比单模光纤和锥形透镜光纤(TLF)作为入纤的耦合效率分别提高了24.827 dB和16.22 dB,为多量子阱-平面光波光路芯片尾纤封装技术提供了实验原型。

Alignment and Coupling between Planar Lightwave Circuit Chip and Wedge-Shaped Fiber

An approach to alignment and coupling between wedge-shaped fiber (WSF) and semiconductor multiple quantum well planar lightwave circuit (PLC) chip integrated with two-dimensional spot size converter (SSC) was presented. Using staircase concatenation method (SCM), the optimum coupling conditions were achieved for wedge-shaped fiber wedge angle, cylindrical endface lens curvature radius, semimajor axis of planar lightwave circuit elliptical field, aspect ratio of planar lightwave circuit elliptical field, misalignment tolerance between wedge-shaped fiber and planar lightwave circuit to be 45°, 2.5 μm, 3.5 μm, 5 μ, 5.5 μm respectively. The output spot of wedge-shaped fiber was experimentally characterized by inverse deducing method (IDM). Compared with the staircase concatenation method computation, the error for the semimajor axis was 3.125%, while that for the semiminor axis was 0.8%. 1.55 μm signal laser was injected into planar lightwave circuit from SMF, tapered and lensed fiber (TLF), wedge-shaped fiber separately as planar lightwave circuit input fiber with the same SMF as output fiber. The coupling efficiency for wedge-shaped fiber was 24.827 dB and 16.22, dB higher than that of SMF and TLF, and therefore an experimental prototype of wedge-shaped fiber-planar lightwave circuit-SMF coupling linkage was established for pigtailed planar lightwave circuit packaging technique.